This amended proposal describes the development of methods to estimate population needs for restorative and prosthodontic treatment using data collected during epidemiologic surveys. These needs, which represent a majority of all dental treatment and dental expenditures are an expression of a populations' "restorative oral health status," currently cannot be estimated accurately because present methods are based on the prevalence of disease, while the majority of needed treatment is associated with dental "conditions" rather than frank disease. Objective criteria for describing and quantifying such conditions have not been developed and the normative treatment needs associated with the presence of these conditions also are not known. The development of these methods occurs in four independent and overlapping phases over five years. In the first phase, criteria are developed and refined that quantify and/or categorize a variety of oral conditions not associated with disease. The criteria calibration phase then uses a panel of general dentists to identify the professionally defined, or normative treatment needs associated with these conditions. This information serves as input for the third phase, in which a model is developed for estimating a population's restorative and prosthodontic normative treatment needs from disease and non-disease conditions determined in epidemiologic surveys. The final phase of the project is a validation of this model, wherein the model's estimates are compared to actual treatment recommended to and received by a sample of adult patients in the community. The resultant ability to quantify restorative and prosthodontic treatment needs of a population from epidemiologic surveys is important in several respects. First, the ability to elicit the epidemiology of the non- disease conditions that are determinants of the majority of all dental treatment should facilitate development of prevention methods for these conditions. More importantly, the estimates of treatment needs are indicators of restorative oral health status. Their development represents a first step in the larger process of evolving population-based assessments of overall oral health status. The assessments also represent quantifiable patient-based outcomes that offer the opportunity to evaluate the effectiveness of diagnostic, preventive and treatment protocols and systems.